The present disclosure relates generally to bypass diode cells. In particular, bypass diode cells configured to form bypass diode cell modules that may be used to direct electric current away from shaded portions of photovoltaic panels to inhibit or prevent the panels from malfunctioning. In addition, fully integrated bypass diode cell modules with improved heat dissipating characteristics are described.
Many known bypass circuits used in photovoltaic systems are unsatisfactory. For example, many existing circuits include Schottky diodes that are ill-suited for handling the level of current and heat to which they are often exposed when the bypass circuit is engaged due to photovoltaic solar module panel shading during normal operation. Many conventional Schottky diodes include axial-leaded or jumper-wire based packages that include thin wires connected, often by solder, to one or both of the diodes' terminals. The solder junctions where these wires are connected to diodes' dies may define “solder voids” formed when connecting the wires. These solder voids may impede heat dissipation from diode's die when a current is applied to a corresponding die.
Further, because the tips of wires used are small, they are soldered to only a relatively small area of the diodes' dies to form little direct contact. This is an inadequate design to support the levels of current typically passing through bypass diodes during operation. Further, this minimal contact reduces the wires' ability to direct heat away from the dies.
These and other shortcomings of conventional bypass diode circuit designs cause bypass diodes to generate and trap excessive heat during operation. In many conventional bypass circuits, this can lead to catastrophic equipment failure. Equipment failure may lead to expensive maintenance, repairs, parts replacement, and downtime.
Despite conventional bypass diodes' insufficient thermal regulation measures, most bypass circuits (or junction boxes housing them) do very little to promote heat dissipation away from bypass diodes or the bypass circuit. Many conventional bypass circuits include diodes that are electrically connected to photovoltaic panels in a plastic junction box that protects against environmental damage, but the plastic housing also denies the bypass circuit effective means to dissipate heat and thus traps heat inside the bypass circuit. The combination of deficiencies in bypass diode structure and bypass circuit design force bypass diodes to operate at unacceptably high temperature levels, which either reduces their reliability or results in catastrophic failure.
Indeed, in many conventional bypass circuits, diodes are simply positioned within an enclosed space within a junction box. Often no additional measures are taken to regulate their operating temperature, either with the junction box or the physical design of the circuit. Accordingly, many conventional bypass circuits fail to include appropriate physical structures that regulate heat and avoid malfunctions.
Thus, there exists a need for diode circuits, and modules including the same, that improve upon and advance the design of known diode circuits. Examples of new and useful diode cell modules relevant to the needs existing in the field are discussed below.
Disclosure addressing one or more of the identified existing needs is provided in the detailed description below. An example of a reference relevant to photovoltaic bypass systems include U.S. Patent References U.S. Pat. No. 7,291,036. The complete disclosure of the above patent is herein incorporated by reference for all purposes.